Visible-Light Photocatalytic Tri- and Difluoroalkylation Cyclizations: Access to a Series of Indole[2,1-a]isoquinoline Derivatives in Continuous Flow

A process for achieving photocatalyzed tri- and difluoromethylation/cyclizations for constructing a series of tri- or difluoromethylated indole[2,1-a]isoquinoline derivatives is described. This protocol utilized an inexpensive organic photoredox catalyst and provided good yields. Moreover, the combination of continuous flow and photochemistry, designed to provide researchers with a unique green process, was also shown to be key to allowing the reaction to proceed (product yield of 83% in flow vs 0% in batch).

Automated summary

The process describes a photocatalyzed tri- and difluoromethylation/cyclization for constructing a series of tri- or difluoromethylated indole[2,1-a]isoquinoline derivatives. It utilized an inexpensive organic photoredox catalyst and showed good yields. The combination of continuous flow and photochemistry proved to be key in allowing the reaction to proceed effectively, with 83% product yield in flow compared to 0% in batch.